Machining Processes Quiz

Production Technology - Introduction to Machining Operations

• Machining is a complex process that uses a sharp cutting tool to remove excess metal and create components with precise geometrical shapes. It is essential in manufacturing, allowing for the production of intricate designs unattainable by other methods. Machining efficiently eliminates unwanted material remaining from processes like casting or forging, making it crucial in the production chain for achieving finished products. It's vital for industries requiring precision, such as aerospace, automotive, and medical, where component reliability impacts functionality. However, machining has downsides: it can result in significant material loss, requires skilled operators for quality output, and involves high initial investment costs, posing challenges for smaller businesses and startups.

Machining Technology Definition

• Machining is a material removal process involving a sharp cutting tool to mechanically remove material, creating chips from excess metal and the desired part geometry.
• Machined parts come in rotational (cylindrical or disk-like) and non-rotational (prismatic, block-like or plate-like) shapes.

Types of Machining Operations

• Traditional Machining:
  • Cutting:
    • Circular Shapes: Turning, Boring, Drilling
    • Various Shapes: Milling, Planning, Shaping, Broaching, Sawing, Filling, Gear forming, Gear generating
• Non-traditional Machining:
  • Chemical Machining (CHM)
  • Electrochemical Machining (ECM)
  • Electrochemical Grinding (ECG)
  • Electrical Discharge Machining (EDM)
  • Laser Beam Machining (LBM)
  • Abrasive Jet Machining (AJM)
  • Water Jet Machining (WJM)
  • Plasma Beam Machining (PBM)
  • Ultrasonic Machining (USM)

Turning Process

• A single-point cutting tool removes material from a rotating workpiece to create a cylindrical shape.
• Performed on a machine tool called a lathe.
• Turning tools can be solid or brazed insert types.
• Specific angles of the cutting tool (e.g. side rake, end cutting edge angle) are important factors.

Motions in Machining Process

• Cutting operations are completed using primary and secondary motion.
  • Primary (Main) Motion: The main cutting motion responsible for material removal, measured by cutting speed.
  • Secondary (Feed) Motion: The motion expanding cutting motion to the entire required surface, measured by cutting feed.
  • Adjustment (Depth) Motion: The motion responsible for tool and workpiece interference, measured by depth of cut

Cutting Parameters (Turning)

• Speed (v): The rate of workpiece rotation (e.g., in RPM).
• Feed (S or f): The rate at which the tool moves along the workpiece (e.g., inches per minute).
• Depth of cut (t or a): The depth to which the tool removes material (e.g., inches or millimeters).

Engine Lathe

• Components: Headstock, Gear levers, Chuck, Coolant Supply, Top Slide, Toolpost, Tailstock, Leadscrew, Motor Lever, Cross Slide, Saddle Handle, Feedshaft, Saddle, Emergency Stop, Lathe Bed

Turning Operations

• Various types: Facing, Taper turning, Form turning, Contour turning, Chamfering, Cutoff, Threading, Boring, Drilling, Knurling

Methods of Holding Workpieces in a Lathe

• Between centers
• Chuck
• Collet
• Face plate

Milling Process

• Machining operation where the workpiece is fed past a rotating tool with multiple cutting edges (teeth).
• The cutting tool is called a milling cutter.
• The machine is called a milling machine.

Milling Cutters (Types)

• Roughing End Mill
• Slab Mill Cutter
• End Mill Cutter
• Ball Mill Cutter
• Hollow Mill Cutter
• Wood Ruff Cutter
• Thread Mill Cutter
• Fly Cutter
• Face Mill Cutter
• Hobbing Cutter
• Dovetail Cutter
• Involute Gear Cutter
• Slide and Face Cutter

Milling Process (Types)

• Peripheral Milling: Cutter axis parallel to surface being machined, cutting edges on the outside periphery of the cutter.
• Face Milling: Cutter axis perpendicular to the surface, cutting edges on both end and outside periphery.

Milling Machines (Types)

• Horizontal Milling Machine,
• Vertical Milling Machine
• Parts: Arbour, Cutter, Column, Overarm, Worktable, Saddle, Knee, Base

Motions and Cutting Parameters in Milling:

• Speed (v): The rate of tool rotation.
• Feed (S): The movement of the workpiece.
• Depth of cut (t): The cutting depth

Milling Operations

• Surface Milling
• Slotting
• T-Slot Milling
• Dovetail Milling
• Angular Milling
• Form Cutting
• Straddle Milling
• Gang Milling
• Slab Milling

Drilling Process

• A machining operation creating a round hole in a workpiece.
• The cutting tool is called a drill (e.g. twist drill).
• Machine tool: Drilling Machine

Twist Drill (Parts)

• Overall Length
• Flutes Length
• Shank
• Drill Diameter
• Flutes Land
• Hardened HSS Body
• Margin
• Shank Diameter
• Point Angle

Drilling Machines

• Bench drill
• Radial arm drill
• Up-right drill -Components: Column, Arm, Mc, H/Worktable, Adjustable head, Fixed head, Spindle, Table, Base

Motions and Cutting Parameters in Drilling

• Speed (v): The rate of twist drill rotation
• Feed (S): The rate at which the workpiece moves
• Depth of cut (t): The cutting depth

Drilling Operations

• Reaming
• Tapping
• Counterboring
• Countersinking
• Center drilling
• Spot facing

Drilling Operations (Processes)

• Reaming: Enlarging the hole for closer tolerances and desired finish.
• Boring: Enlarging a drilled hole.
• Counter Boring: Enlarging the hole diameter to a desired depth.
• Counter Sinking: Enlarging the top end of a hole.
• Spot Facing: creating a true seat for bolt head.
• Tapping: Creating internal threads in an already drilled hole.

Shaping Process

• Operation used to produce relatively small, flat surfaces.
• Single-point tool mounted on a reciprocating ram on a tool box.
• Workpiece is clamped in a vice.
• Cutting action occurs during the forward stroke of the tool.
• Return stroke is idle.

Shaper and Planner Machines

• Components: Toolhead, Workpiece, Worktable, Ram, Crossrail, Column, Base, Speed, Feed.
• Shaper machine: Workpiece moves, tool stationary.
• Planner machine: Tool moves, workpiece stationary

Shaping Operations

• Facing horizontal surfaces
• Facing vertical surfaces
• Machining of racks

Motions and Cutting Parameters in Shaping

• Speed (v): The rate of tool reciprocation.
• Feed (S): The workpiece travel rate.
• Depth of cut (t): The cutting depth of the tool.

CNC Machines

• Computerized Numerical Control (CNC) machines use programmable automation (computer control) using numbers and letters to manage machines like lathes, mills and grinders.